Lean Root Cause Analysis
Root cause analysis is the process of reducing an issue down to a simple proposition: What are we trying to accomplish?
When most people refer to Root Cause Analysis they truly understand the meaning: Identifying the core issue that, if resolved, through Corrective Action, will not recur.
RCA is many times coupled with other terminology and quality tools:
- RCCM – Root Cause Counter Measure
- Corrective Actions
- CAR’s – Corrective Action Requests
- CAPA – Corrective Action Preventative Action
These are just some Quality tools associated with Root Cause Analysis:
- Ishikawa (Fishbone)
- 5 Why’s
- Causal Diagrams
- Affinity Diagrams
- PDCA – Plan-Do-Check-Act
Other Quality programs like Six Sigma build on the 5 Why’s and the PDCA activities and advance the effort with DMAIC – Define-Measure-Analyze-Improve-Control.
Frequently the problem is not understanding the objective, but rather understanding the process and truly identifying the Root Cause. Often times the tools themselves can create challenges. For example, for a 5 Why’s exercise to yield meaningful information, the problem statement must be accurate and well defined. That alone can generate issues.
While analyzing data and using brainstorming techniques may actually identify multiple Root Causes, ultimately Corrective Action is the illusive target. If a CAR has ever been closed because the Corrective Action was to “Retrain the Operator”, we should now understand that true Root Cause has not really been uncovered. We know this because we observe retrained operators duplicating errors. Clearly retraining is not a Corrective Action. Keep digging deeper.
Three basic responses in Root Cause Analysis:
1. Counter Measure
Meeting the threat or failure head on, dealing with the issue immediately. Think Fighter pilot flying over enemy territory and being targeted by a missile. He releases flares to confuse the missile and immediately takes evasive action.
- Root Cause? The missile and the missile site
- Counter Measure? Get Away!
2. Preventative Action
What can be done to avoid the threat? To avoid the opportunity to make defects? This second level activity acknowledges that we haven’t truly created Corrective Action yet, but we want to put some processes or procedures in place to try to mitigate the potential until we can implement Corrective Action. Think Fighter pilots marking maps in such a way that future missions avoid the hostile area. Can they still make the mistake and fly into a hostile zone? Yes! This is why training is not Corrective Action.
- Root Cause? The Missile site
- Preventative Action? Avoid the Area
3. Corrective Action
When true Root Cause is identified, a Corrective Action is needed. Real Corrective Action often is difficult to achieve. If the Corrective Action can’t eliminate the chance of a failure, it is not Corrective Action.
- Root Cause? The Missile site
- Corrective Action? Destroy the Missile site.
Start with good Root Cause Analysis. Use the quality tools to drive to the core issue or issues. Then evaluate what response is possible, always targeting Corrective Actions.